1. Field of the Invention
The present invention relates to an olefin polymerization catalyst and a process for producing an olefin polymer with the catalyst. More specifically, the present invention relates to an olefin polymerization catalyst which contains neither an organoaluminum oxy-compound nor an organoboron compound conventionally used as a catalyst component for olefin polymerization, and to a process for producing an olefin polymer with the catalyst.
2. Related Background Art
Recently, the transition metal compounds and lanthanoid compounds containing two or more atoms selected from B, N, O, S, and Se are attracting attention as highly active catalysts for olefin polymerization, as shown, for example, by the papers below:    (1) Brookhart et al., J.Am.Chem.Soc., 117, 6414, (1995)    (2) Brookhart et al., J.Am.Chem.Soc., 118, 267 (1996)    (3) Brookhart et al., J.Am.Chem.Soc., 118, 11664 (1996)    (4) Brookhart et al., J.Am.Chem.Soc., 120, 4049 (1998)    (5) Gibson et al., Chem.Commun., 849 (1998)    (6) McConville et al., Macromolecules, 29, 5241 (1996)    (7) Jordan et al., Organometallics, 16, 3282 (1997)    (8) Collins et al., Organometallics, 18, 2731 (1999)    (9) Eisen et al., Organometallics, 17, 3155 (1998)    (10) Eisen et al, J.Am.Chem.Soc., 120, 8640 (1998)    (11) Jordan et al., J.Am.Chem.Soc., 119, 8125 (1997)    (12) Hakala et al., Macromol.Rapid Commun., 18, 635-638 (1997).
In known processes, however, these catalysts are necessarily used in combination with an expensive organoaluminum oxy-compound or organoboron compound for high olefin polymerization catalyst activity. The high olefin polymerization catalyst activity obtained in combination with the expensive organoaluminum oxy-compound or organoboron compound can be kept only for a short time: the high activity for an olefin polymerization is not retainable for a long time, for example 30 minutes or longer, which period is adopted in the conventional industrial production process.
Therefore, the catalyst is desired which has higher polymerization activity without the expensive organoaluminum oxy-compound or organoboron compound and which has a higher activity for a long catalyst life, such as 30 minutes or more, in polymerization in a conventional industrial process.